Couple of my cars (old ones) came with electric f/pump originally - the big-engine one has TWO!!!! I usually run electric fuel pumps on hot rods for a couple of reasons - if you ever run out of gas (some of the tanks are not large), you don't have to prime the carb(s) - this assumes, of course, that you're using at least a group22 battery. Another reason (this is largely esthetic) is that it is a modification...and that's part of hotrodding. Electric pumps can provide some serious danger also - if you are in an impact/rollover that breaks a fuel line/ruptures or upends the tank, and the ignition key is on....fuel goes all over the place. You need to wire up a cutoff switch to your oil pressure guage - when O/P drops below 5 lbs psi....fuel pump shuts off. You can actually (and I do this on one of my cars) put an on/off toggle for the fuel pump in or near the instrument panel. Turn off the fuel when you're shutting the car down for the night....engines dies, then you shut everything off. This is how you turn off aircraft - cut off the fuel, then the master switch. When you're ready to depart, turn on the key...then the f/p switch...and in a few moments, you're "good to go". I just like 'em....but, I'm one of those guys that likes to do wiring and engineering (small mounts, where to put stuff, how to make it work best). Certainly nothing wrong with mechanical pumps, NASCAR used them for years - they may still do so...dunno - I quit watching NASCAR when the WWF fans started crowding the bleachers with their low-intellect drooling and mewling. "the true test of a man's honor is what he would risk to keep it" dj
I run both. The mechanical pulls through the electric. For around town the mechanical is fine but the electric really helps when I'm getting on it. Te electric is also good to prime the carb if I haven't driven her for a while.
Well that seems kinda cool? Excessive use of fuel though? Im going for the most efficient way to run my setup here. Not necessarily FUEL efficient, just mechanical efficiency... For I am not the HANDIEST! The electric fuel pump has been giving me problems since I bought the car. Does the mechanical pump make the car harder to start? (ie priming and such...)
both work well, I run a mech. pump, less wireing and you can ushally get one that will pump plenty enough for most hp engines! as long as the pump you get flows as much and runs same psi you should be fine. A cheapy ushally pumps about the same as a stock pump.
mechanical pump will work just fine. Not the danger issue either. Electric is a good, cheap alternative when an old mechanical pump craps out. Sometimes their is no alternative. it's more a matter of choice.
as long as yer car doesnt set a long time and your carb doesnt leak it wont change anything. later cobey/om71
Adding the mechanical pump back is a good idea. When done, I would treat it as the primary, keep the electric as a backup, normally off, with a switch to turn it on when/only needed. With mechanical pump when motor quits the pump quits feeding fuel. One safety issue with electric if there is a leak and fire, motor will probably quit and pump might keep feeding the flames, another reason to use elect only as a backup to engine driven mechanical.
I run mechanical only. I've seen electrics not get out of the garage. Plus sure as shooting if the electric pump goes out in BFE no one will have one that fits like/where the old one did. But then again I run a Chevy and what parts store doesn't carry a Chevy pump?
I've been running electrics on both of my cars. Both are SW 12 volt pumps with max flow of 7 psi. I always carry a spare on long trips since both pumps are about 15 years old. i also run dual filters, one between the tank and the pump and the other before the carb(s). I have never had any problems.
I'm a big fan of the setup Kerry talked about. The electric is just for when you want to get on it and for priming, and is controlled with a switch on the dash. Makes for quick starts on a car you don't drive everyday and makes a good backup. Only safety thing when running the two pump system is that if, for some reason, your mechanical pump gets a hole in the rubber diaphragm, the electric pump will pump the contents of the fuel tank into your crankcase. Not likely to ever be a problem, but something to be aware of, and a reason to not drive around with the electric pump on all the time.
I don't know if it would be the same with gasoline or not. I have a Ford Diesel that I put an electric pump on just for priming if I ran out of gas. (diesels are a bitch if ya run it out of gas). I never used it very much, in fact I never used it at all. I guess cooties from the diesel got into it and stopped it up. It ran me nuts for awhile tryin' to figure out what was goin' on. I though it was the mechanical pump, replaced that, thought it was the fuel filter, replaced that and finally found it to be that electric pump stopped up. I had one on my old '67 Ford PU with a 429 in it and I never used it either and it worked fine always. I'm going to put one on the '56 just for this vapor lock problem.
I use both. Modern gasoline has been formulated for a closed fuel (fuel injection) system, and has a SUPER low pressure of vaporization. On my DeSoto Hemi (Stock 345, 2X4's), when I turn it off the hot engine boils off the fuel in the carburetors. When it sits for a few days, without being run, the fuel will evaporate. So I turn the key on, hit the under-dash switch (like PROP WASH does) and wait for the carbs to refill.. then start the engine without having to grind the starter until the carbs fill. The electric pump is GREAT for vapor lock, like when it's really hot out and you have to idle for a long time. Got mine from Sacramento Vintage Ford, and its a 3-6 lb. pressure, 6V Positive (+) ground, draw through model...which means that when it's off, the mechanical pump will be able to pull fuel through it. I leave it off, most of the time, and the Stock mechanical pump feeds both carbs fine. However, it's a life saver for the things I mentioned, and if you DO run out of gas...
I use a commonly found GM electric fuel pump and a Ford inertia switch. Solves both the valid points mentioned regarding safety and vaporlock. Its mounted in the tank, so it's quiet and nobody can fuck with it. Its also wired into the security system - another bonus. And yes, some parts stores are already not stocking Chevy mechanical fuel pumps, and thats just gonna get worse.
As said in the above, the electric back up is a good way to solve many problems that we all have. An old-timer from around here is helping me do this to my car this winter, which has a mechanical pump. Have a switch to shut it off when not in use and you are good to go.
We aren't talking about a sprint car or an airplane here. How many street miles do they see? A street driven vehicle has a much wider range of fuel requirements than either of them.
I prefer an electric pump, usually tied in with a relay that will kill it if you loose oil pressure. The inertia switch is a good idea as well. I always ran a regulator - usually a Holley I generally use Carter pumps, Only had one bad one. In fact the Carter Heavy Duty is the electric lift pump used on Cummins Diesels. I mount the pump under the car on the frame near the fuel tank. A small sheet metal cover keeps road debris from impacting it. A simple fuel strainer in front and a fuel filter after, all tucked up and hidden. Works great to drain fuel to pull the tank, prime the system when you run out of fuel, etc. Then again, its your car, do what you want.
I am a fan of mechanicl fuel pumps, and will run them if I can on my projects. I just like their simplicity, they either work, which is usually the case, or they don't... When they don't, I always know what the problem is. Also, it seems that most "good" electric pumps make a shit load of noise, I don't like that much.... I prefer to hear the engine running over the fuel pump. Unfortunatly I have not been able to use one on either of the last two Ford powered projects because of parts issues of one kind or another...
I would run a mechanical on my Olds, mainly because most electrics are noisy, and there is nothing traditional about a noisy modern electric pump but the Hurst mounts are in the way I geuss I need to find a quieter pump.
I've got a Carter pump on the Pusher (70 GPH) it works OK for driveing but when I'm scooting down the 1320 it has a tendency to starve on the big end. So I'm going back to electric (110 GPH). But you may not need that much fuel. I dunno you may need more than that its just a matter of what it takes to keep your mill fed. I'm not big on the whole asthetic thing, I think that form follows function, so if you need more fuel you need to upgrade your pump. Basically you need 1/2 lb fuel per HP per hour @ WOT. A gallon of gas weighs about 6 LBS. That would be (HP x .5) to get the LBS per hour. (LBS/6) to get gallons per hour. This will ballpark you it isn't going to be the magic number in every situation. Multiple carbs or forced induction or (heaven forbid) Nitrous Oxide for example, will effect the number but it is a starting place.
I'm another fan of the simplicity of a mechanical pump. I used a high volume Carter on my coupe when it was carbureted, and ran sub 1.30 60 ft and 9.50 ets without any starvation problems. Used a little Holley regulator, just like with an electric pump. I don't see any reason that wouldn't work on the street. Plus there's some stealth value by not using the electric pump.
I have always wondered about using a TBI external inline electric pump. Those have the reliability without all the noise. They used them in the mid to late 80's before the in the tank setups. Don't remember what on. You could regulate it and send the rest back to the tank.
when posible i run a carter mechanical on my cars. sometimes a engine swap or something makes an electric necessary. cheap fuel pumps are a bad idea either elctric or not. go with a good one either way and you will be fine
I like the electric ones. To me it's like instant gas, it's either on or off. Sometimes some of my off topic cars set for awhile and I can crank and build up oil presure before the engine starts, then I turn the fuel pump on after I have oil pressure and give it pump and it starts right up. The Electric also gives you a couple of more Horse Power. Because the Cam doesn't have to activate the fuel pump arm on every revolution. I heard at least 5 more HP but I am not sure about that, an electric pump should give you 7 lbs of pressure that remains pretty constant except for some spikes when hammering the throttle that's with a Holley 750 double pumper. A hidden switch on the fuel pump can give you some insurance on some one trying to steal the thing also.
If you're not handy, then why re-invent the wheel? There will probably be some tubing work to switch over to mechanical. Just replace your old fuel pump with a good brand and be done with it....and install an in-line filter if you don't have one already. My 2 cents.
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